In a letter to Appropriations Committee Chairwoman Barbara Mikulski, Johanns cited report Friday in the Washington Post, wherein the IRS acknowledged "that it flagged political groups with 'tea party' or 'patriot' in their names for special scrutiny when they applied for tax-exempt status."

The Subcommittee on Financial Services and General Government, which Johanns serves as the top Republican, has oversight of the IRS budget.

The IRS reportedly gave increased scrutiny to political groups based on ideology as far back as 2010, according to information leaked from an Inspector General's investigation. Groups calling for reduced government spending were targeted, and in some cases asked for their donor lists, which is against most IRS policies, Johanns said.

"If these reports are accurate, it is extremely troubling that the IRS, an agency with unprecedented impact on the lives of millions of American taxpayers, is executing the laws with which they are entrusted in a politically motivated manner," Johanns said.

“I hope IRS is not acting as the political watchdog for this Administration, but the facts seem to suggest otherwise," Johanns said. “Every Member of Congress, regardless of party, owes it to the American people to demand answers about this disturbing practice – including who knew about it and when, who authorized it, and why it was allowed to continue in secrecy for so long.”

According to the Washington Post, the IRS acknowledged Friday that it flagged political groups with “tea party” or “patriot” in their names for special scrutiny when they applied for tax-exempt status.